OLED apparatus has the advantages such as all-solid-state structure, high brightness, full viewing angle, quick response, wide working temperature range, capable of achieving flexible display, and therefore has become a competitive and promising new generation of display technology. The organic light emitting material and the cathode material of the OLED apparatus are sensitive to moisture and oxygen, a service life of the OLED apparatus may be influenced adversely in a wet or high-oxygen-content environment.
In order to prevent moisture and oxygen from influencing adversely the OLED apparatus, the OLED apparatus is required to be packaged. In the process of packaging, the OLED array substrate is adhered to a packaging substrate by a sealant, thereby to form a sealed apparatus structure and block moisture and oxygen in the air. A spacer is arranged between the OLED array substrate and the packaging substrate, so to support them and form a cell gap therebetween.
A top light-emitting OLED apparatus is generally provided with a relative thin cathode so as to achieve a relative high light transmittance. However, a surface of the OLED array substrate is not even, a lap joint of the thin cathode may be poor at an uneven portion of the surface of the OLED array substrate (e.g., where the spacers are located), therefore a cathode resistance may be increased and a power consumption of the OLED array substrate may be increased as a result. Nevertheless, the light transmittance of the OLED array substrate may be decreased and then the display effect may be influenced adversely if the cathode is thick.